Physics for Kids

Elementary Particles - Quarks, Bosons, Leptons

What is an elementary particle?

An elementary particle is a particle that is not made up of any smaller particles. Elementary particles are the building blocks of the universe. All the other particles and matter in the universe are made up of elementary particles.

History

For many years scientists thought that the atom was the smallest particle possible. Then they learned that the atom was made up of even smaller particles. When we studied the atom we learned about the basic particles of the atom including the electron, proton, and neutron. Today, scientists have found even smaller particles that make up the proton and the neutron.

Types of Elementary particles

We won't go into a lot of detail on these particles, but it is interesting to know the names of some of these particles and how they make up larger particles such as the proton and neutron.

There are two main categories of elementary particles: fermions and bosons.

Fermions

Fermions are the matter particles. All matter is made up fermions. Fermions are divided into two types of particles: quarks and leptons.

Quarks - Quarks are the basic building blocks for protons and neutrons. There are six types of quarks and they have pretty interesting names including up, down, charm, strange, top, and bottom. The different types of quarks are called "flavors" by physicists.

Leptons - One type of lepton that you have probably heard of is the electron. Electrons are important building blocks for atoms. Other types of leptons include the muon and the tau.

A proton is made up of three quarks

Bosons

Bosons are force-carrying particles. This means that they are made up of tiny bundles of energy.

Photon - Light is made up of a type of boson called a photon. You can learn more about photons and light here.

Gluons - Another type of boson is the gluon. Gluons act as the force-carrier between quarks in creating one of the fundamental forces of nature, the strong force.

Proton

A proton is made up of three quarks including two "up" quarks and one "down" quark.

Neutron

A neutron is made up of three quarks including two "down" quarks and one "up" quark.

Fun Facts about Elementary Particles

Some scientists say that the electron is not an elementary particle and is actually made up of two smaller particles.

Particles made up of quarks are called hadrons.

A bunch of gluons bound together is called a glueball.

A tachyon is a hypothetical particle that travels faster than the speed of light.

Quarks and gluons are said to have a "color charge" as well as an electric charge. A proton is made from a blue up quark, a red up quark, and a green down quark (see the picture above in the page).